Electrophotographic lithographic printing plate precursor

Abstract

An electrophotographic lithographic printing plate precursor is described which utilizes an electrophotographic photoreceptor comprising a conductive support having provided thereon at least one photoconductive layer containing photoconductive zinc oxide and a resin binder, wherein said resin binder comprises at least one resin which contains at least one kind of functional group capable of producing at least one carboxyl group through decomposition and is crosslinked at least in part to bring about improvements in background stain resistance and printing durability.

What is claimed is: 
     
       1. An electrophotographic lithographic printing plate precursor which utilizes an electrophotographic photoreceptor comprising a conductive support having provided thereon at least one photoconductive layer containing photoconductive zinc oxide and a resin binder, said resin binder comprising a partially cross-linked resin which contains at least one kind of functional group capable of producing at least one carboxyl group through decomposition, said cross-linking being sufficient to improve the stain resistance of the non-image area of the printing plate. 
     
     
       2. An electrophotographic lithographic printing plate precursor as in claim 1, wherein said resin is a resin of the kind which contains at least one copolymer constituent having at least one kind of functional group capable of producing at least one carboxyl group through decomposition, and has in advance such a cross-linking structure as to become slightly soluble or insoluble in water when the carboxyl groups are produced by the decomposition. 
     
     
       3. An electrophotographic lithographic printing plate precursor as in claim 1, wherein said resin is a resin containing at least one kind of functional group capable of producing at least one carboxyl group through decomposition and at least one kind of functional group capable of undergoing a curing reaction by heat or light. 
     
     
       4. An electrophotographic lithographic printing plate precursor as in claim 2, wherein said resin has a molecular weight of from 5×10 3  to 5×10 5 . 
     
     
       5. An electrophotographic lithographic printing plate precursor as in claim 1, wherein said functional groups is contained in an amount of from about 1 to about 85 wt % based on the total weight of the resin binders. 
     
     
       6. An electrophotographic lithographic printing plate precursor as in claim 2, wherein said coplymer component having a cross-linking structure is present in an amount of from 0.1 to about 10 wt %, when the copolymer component contains polymerizable double bonds, or in an amount of from 1 to 80 wt %, when the copolymer component contains cross-linkable groups other than the polymerizable double bonds. 
     
     
       7. An electrophotographic lithographic printing plate precursor as in claim 1, wherein said resin is a resin containing at least one kind of functional group represented by formula (I):   --COO--L.sub.1                                             (I)     wherein L 1  represents ##STR62## --N=CH--Q 1 , ##STR63## R 1  and R 2  each represents a hydrogen atom or an aliphatic group; X represents an aromatic group; Z represents a hydrogen atom, a halogen atom, a trihalomethyl group, an alkyl group, --CN, --NO 2 , --SO 2  R 1 , (wherein R 1 , represents a hydrocarbon group, --COOR 2 , (wherein R 2 , represents a hydrocarbon group), or --O--R 3 , (wherein R 3 , represents a hydrocarbon group); n and m are each 0, 1, or 2; R 3 , R 4 , and R 5  each represents a hydrocarbon group, or --O--R 4 , (wherein R 4 , represents a hydrocarbon group; M represents Si, Sn, Or Ti; Q 1  and Q 2  each represent a hydrocarbon group; Y 1  represents an oxygen atom, or a sulfur atom; R 6 , R 7 , and R 8  each represents a hydrogen atom, a hydrocarbon group, or --O--R 5 , (wherein R 5 , represents a hydrocarbon group); p represents an integer of 3 or 4; and Y 2  represents an organic residue to complete a cyclic imido group.   
     
     
       8. An electrophotographic lithographic printing plate precursor as in claim 1, wherein said resin is a resin containing at least one kind of functional group represented by formula (IV):   --CO--L.sub.2                                              (IV)     wherein L 2  represents ##STR64## Wherein R 13 , R 14 , R 15 , R 16  and R 17  each represents a hydrogen atom, or an aliphatic group.   
     
     
       9. An electrophotographic lithographic printing plate precursor as in claim 1, wherein said resin is a resin containing at least one kind of oxazolo ring represented by the formula (V): ##STR65## Wherein R 18  and R 19  each represents a hydrogen atom or a hydrocarbon group, or they may combine with each other to form a ring. 
     
     
       10. An electrophotographic lithographic printing plate precursor as in claim 1, wherein said partially cross-linked resin is one which is formed through polymerization using monomers containing two or more of polymerizing functional groups, said monomers containing two or more polymerizing functional groups being present in a proportion of from about 0.1 to about 10% by weight based on the total monomers. 
     
     
       11. An electrophotographic lithographic printing plate precursor as in claim 1, wherein said partially cross-linked resin is one which is formed by a cross-linking reaction in a polymer containing a cross-linking functional group-containing copolymer constitutent in an amount of from 1 to 80% by weight. 
     
     
       12. A process for forming an electrophotographic lithographic printing plate precursor, comprising: (a) mixing photoconductive zinc oxide and a resin; and   (b) coating the mixture of step (a) onto a conductive support to provide a photoconductive layer.   wherein said resin contains at least one kind of functional group capable of producing at least one carboxyl group through decomposition.   wherein said resin comprises a cross-linking functional group-containing copolymer constituent in an amount of from 1 to 80% by weight, and   wherein said resin is partially cross-linked before step (a), after step (a), but before step (b), during step (b), after step (b), or during two or more of the above.   
     
     
       13. A process for forming an electrophotographic lithographic printing plate precursor, comprising: (a) mixing photoconductive zinc oxide and a resin; and   (b) coating the mixture of step (a) onto a conductive support to provide a photoconductive layer,   wherein said resin contains at least one kind of functional group capable of producing at least one carboxyl group through decomposition,   wherein said resin is formed by polymerizing monomers containing two or more of polymerizing functional groups, said monomers containing two or more polymerizing functional groups being present in a proportion of from about 0.1 to about 10% by weight based on the total monomers, and   wherein said resin is partially cross-linked before step (a), after step (a), but before step (b), during step (b), after step (b), or during two or more of the above.